A systematic review and meta-analysis by Pramono et al., involving 18 RCTs, that evaluate the effect of vitamin D supplementation on insulin sensitivity in subjects with or at risk for insulin resistance showed that additional vitamin D treatment showed no effect of insulin sensitivity, with a standardized mean difference of − 0.01, 95% CI − 0.12, 0.10; p = 0.87, I2 = 0%15. Here, INS is linked to Insulin resistance.